Membrane proteins play critical functions in many if not most cellular and physiological processes. Single membrane proteins and their macromolecular assemblies are essential catalysts in the metabolism and conveyance of information and energy between cells and the external environment, between cellular compartments and in the interactions of cells with viral and other agents. Membrane proteins are vital to human health, specific defects can be associated with human disease and many are the targets of a large number of pharmacologically and toxicologically active substances. Recently we demonstrated that suitable engineered "membrane scaffold proteins" (MSPs) would self-assemble phospholipids and a variety of membrane protein targets into nanoscale discoidal bilayer structures. These nominally 10 nm diameter particles, termed Nanodiscs, are rendered soluble in aqueous solution via the amphipathic helical nature of the encircling MSP. We have also shown that the model seven-trans-membrane protein bacteriorhodopsin (bR) could be functionally solubilized and incorporated into homogeneous and monodisperse Nanodiscs. In this STTR application, we seek support for a synergistic collaboration of corporate and academic entities to extend these preliminary investigations to the important class of drug targets, the G-protein coupled receptors (GPCRs) and develop and commercialize this technology for use by the academic and pharmaceutical industry. We present enabling data on the human beta-2 adrenergic receptor and provide a research plan focused on defining a simple and robust procedure for solubilizing GPCRs into functional membrane bilayer Nanodiscs for use in elucidating the structure and function of membrane proteins critical to human health.